’98 1.5L Mirage questions

I'm sorry if any of this has been covered recently.

My fiancee has a '98 Mitsubishi Mirage with the 1.5L I4 with 120k miles on it.  I've been driving it lately because I drive a lot more than she does and it gets better gas mileage than my Volvo (and uses cheaper gas)

In the past few months I've noticed some noises and other things happening.

A) It sounds like there is an exhaust leak coming from the front of the engine.  I assumed this is possibly a leaky exhaust manifold gasket.

B) The accelerator pedal is sticky, especially the first time it's pressed during the day.  I'm assuming the throttle body is filthy and I'll get to that today (now that the semester is over).

C) When I turn off the engine, I'm getting increasingly violent vibrations as it shuts down.  I'm thinking motor mounts.

D) Starting Thursday, the engine idles poorly, even lopey (when the A/C compressor is not going) as if it's got a hot cam (and I can assure you, it has no such thing).  At first I was thinking that the Idle air bypass is dirty/clogged, but I started wondering about the timing belt, like maybe it's stretched and the exhaust is opening too soon or staying open too late.  Probably not.  But I called her father and he says he's never changed the timing belt on this car    She got it at 30k miles....

So obviously I'm going to get the timing belt replaced ASAP, but I can't find any repair manuals for this car specifically *anywhere* (locally).  Can someone point me to a good online article that details the changing of the timing belt or, if it's too complicated, how much should I expect to pay?

I'm also looking for thoughts on the above problems, since they should be fairly common.  I'm not familiar with little cars like this, I'm familiar with full sized Fords with pushrod V8s, and have just started learning things about OHC engines when I got my Volvo.

Thanks!

give me your email address i'll send you a page diagram to replace the belt ..the 1.5 is one of the easiest belts to replace

check for an oil leak in the right hand corner of the head !! theres an oil port there that likes to leak due to  head gasket failure left hand rear looking from the front of the car right hand front laying under the car looking up from the rear.

NGK SPARK PLUGS  no auto lites or ac delco and especialy stay away from bosch platinum..

Power brake the car in forward then reverse have some look at how high that engine wants to jump ...best way to check the mounts ...do not rev it then put into gear ...brake first then gas!!!!!!